Metal working dies



Sept. 8.; 1964 1-. F. TRIBE METAL WORKING DIES 2 Sheets- Sheet 1 Filed March 26, 1962 Sept. 8, 1964 T. F. TRIBE METAL WORKING DIES 2 Sheets-Sheet 2 Filed March 26, 1962 United States Patent 3,147,725 METAL WORKING DIES Thomas Francis Tribe, Castle Mill Works, Dudley, England, assignor of one-half to British Federal Welder and Machine Company Limited Filed Mar. 26, 1962, Ser. No. 182,568

3 Claims. (Cl. 113-52) This invention concerns metal working dies such as used for reducing the end of a metal tube either to close the end or to form a neck therein, the shaping operation being performed while the tube is hot or cold. The invention relates to dies for use in shaping a workpiece (e.g. a metal tube) wherein the die is rotated relatively to the workpiece. For convenience a die for this purpose is referred to as a rotary die though the die may be stationary, the workpiece being rotated.

According to this invention a rotary die comprises a body portion and a plurality of angularly-spaced, strip like members carried by the body portion each with an edge projecting from the body for engagement with the workpiece, the projecting edges of said members having profiles such as to shape the workpiece in required manner. Preferably the strip-like members are disposed radially of the axis of the circular die.

It is a feature of this invention that the strip-like members are removable from, and replaceable in, the body portion. In this way sets of differently profiled members may be used in the same body either to produce differently shaped workpieces or to accommodate workpieces of dilferent size e.g. tubes of different diameters.

The members may be between the confronting radial faces of a pair of adjacent sector-shaped elements which constitute the die body. Thus, for example, the die body may have three sector-shaped elements held in a carrier ring and there are three strip-like members, one between the side faces of each pair of sector elements. A strip member may be secured to one of the confronting side faces of a pair of sector elements or to both confronting side faces of the pair of elements. The sector elements may be separated by an insulating layer between the confronting side faces and the layer is disposed between the strip elements when a strip element is secured to both side faces.

Alternatively, or additionally, a sector element (or each such element) may carry a strip-like element or a plurality of angularly-spaced elements-between the side faces of the element.

The strip elements may be secured to the body portion by bolts being located, for instance, by dowel pins.

The strip-like elements are the parts of the die assembly subjected to heavy wear. By providing such elements which are removable and replaceable it is readily possible to re-shape the profiled edges of the elements (e.g. by grinding) to correct for wear and also to modify the profile of existing elements to produce a closure end of slightly different outline to that previously formed by the elements.

This invention particularly concerns a method of closing the end of a metal tube wherein the tube is urged axially towards a circular, multi-part die having converging walls while the die and the tube are relatively rotated and simultaneously passing an electric heating current through the tube from one part of the die to another. By the method of the kind referred to the end of the tube within the die is heated electrically and the axial force on the tube urges the heated end into contact with the converging walls of the die so that the heated metal is caused to converge and close the end of the tube.

Dies according to this invention are illustrated in the accompanying drawings whereof:

FIG. 1 is an end view of one construction of die,

ice

FIG. 2 is a section on the line II-II of FIG. 1, and

FIGS. 3 and 4 are views corresponding respectively with FIGS. 1 and 2 and showing another die construction.

Referring to FIGS. 1 and 2: the die 109 is held stationary and is co-axial with a metal tube 110 which is rotated in the direction of the arrow X. At the same time the tube is moved axially in the direction of arrow Y into an opening 111 of the die.

The die 109 comprises three sectors 113 which are separated by electrically insulating strips 114, the sectors being clamped together by a carrier ring adapted to maintain the electrical insulation of the sectors generally indicated at 115. Each sector is separately connected to a source of electric current supply.

The die 109 comprises a body and three equispaced strip-like members 112. Each member 112 is located in a radial groove formation at the confronting radial faces 116 of a pair of adjacent sectors 113, the member 112 and an insulating strip 114 being sandwiched between said faces. Each member 112 is secured to a sector 113 by bolts 117.

While in the arrangement illustrated only one member 112 lies between each pair of sectors 113 it may be arranged that two members 112 are so provided, each being secured to one of the pair of sectors 113 and the insulating strip 114 being sandwiched between the pair of members 112. The second such member 112 is shown chain dotted in FIG. 1.

The edges 118 of members 112 project from the body of the die (as at 119) for engagement with tube 110 so that the shaping operation on tube 110 and the electrical heat is generated in tube 110 across the members 112 by said members. The members 112 may be relatively wear resistant whereas the body of the die is of a relatively soft material.

In the arrangement of FIGS. 3 and 4 the members 112 are within sectors 113 and each member is received in a radial groove in one sector. The members 112 are bolted at 120 to the die body. The members in this construction project from the die body as above described.

Since the members 112 are removable from, and replaceable in, the die body sets of differently profiled members may be used in the same body either to produce differently shaped workpieces or to accommodate workpieces of different size e.g. tubes of different diameters.

The strip-like elements are the parts of the die assembly subjected to heavy wear. By providing such elements which are removable and replaceable it is readily possible to re-shape the profiled edges of the elements (e.g. by grinding) to correct for wear and also to modify the profile of existing elements to produce a closure end of slightly different outline to that previously formed by the elements.

In use of the rotary dies as described, a tube end within the die is heated electrically and the axial force on the tube continuously urges such heated end into contact with the profiled tool edges so that the heated metal is reduced by being caused to converge to close the tube end or form a neck therein.

In each of the arrangements illustrated it will be seen that the tool members 112 each abut radially outwardly against the shoulder delimiting the respective groove formation so that the backing metal of the sectors 113 resists the generally radial outward force imparted to the tool members.

I claim:

1. A die to reduce the end of a metal tubular workpiece with relative rotation and axial movement between the die and the workpiece, comprising an annular die body constituted by a plurality of separate solid metal sectors, a plurality of electrical insulating layers located in planes radial of the body to separate and insulate said sectors from one another, and a carrier means to releasably hold said sectors and interposed insulating layers clamped together with the said sectors insulated from one another, said sectors each presenting at least one radial groove formation delimited radially outwards by an axially extending shoulder of the sector and presenting an axially extending opening radially inwards of the sector, a plurality of strip-form metal tool members positioned one in each such groove formation abutting radially outwards against said shoulder and presenting axially extending profiled edges which project radially inwards of said die body to engage the workpiece, and means to locate said tool members removably and replaceably in such position, said sectors being separately connectable to an electrical source to provide for passage of heating current through the workpiece during reduction from one sector to another via the respective tool members.

References Cited in the file of this patent UNITED STATES PATENTS r 2,325,479 Crawford July 27, 1943 2,325,481 Crawford July 27, 1943 2,325,498 Floyd July 27, 1943 2,325,522 Lauer et al. July 27, 1943 1 2,335,165 Westin et al. Nov. 23, 1943 2,917,014 Terwilliger Dec. 15, 1959 2,965,059 Terwilliger Dec. 20, 1960 

1. A DIE TO REDUCE THE END OF A METAL TUBULAR WORKPIECE WITH RELATIVE ROTATION AND AXIAL MOVEMENT BETWEEN THE DIE AND THE WORKPIECE, COMPRISING AN ANNULAR DIE BODY CONSTITUTED BY A PLURALITY OF SEPARATE SOLID METAL SECTORS, A PLURALITY OF ELECTRICAL INSULATING LAYERS LOCATED IN PLANES RADIAL OF THE BODY TO SEPARATE AND INSULATE SAID SECTORS FROM ONE ANOTHER, AND A CARRIER MEANS TO RELEASABLY HOLD SAID SECTORS AND INTERPOSED INSULATING LAYERS CLAMPED TOGETHER WITH THE SAID SECTORS INSULATED FROM ONE ANOTHER, SAID SELECTORS EACH PRESENTING AT LEAST ONE RADIAL GROOVE FORMATION DELIMITED RADIALLY OUTWARDS BY AN AXIALLY EXTENDING SHOULDER OF THE SECTOR AND PRESENTING AN AXIALLY EXTENDING OPENING RADIALLY INWARDS OF THE SECTOR, A PLURALITY OF STRIP-FORM METAL TOOL MEMBERS POSITIONED ONE IN EACH SUCH GROOVE FORMATION ABUTTING RADIALLY OUTWARDS AGAINST SAID SHOULDER AND PRESENTING AXIALLY EXTENDING PROFILED EDGES WHICH PROJECT RADIALLY IN- 